12.8. Invoices

Generally, you have two options for invoices. The first method has a field on the master bill record that says whether or not an invoice was created. If it was not created, you could add/change items in the bill detail. If it was created, it would be a good idea to lock those fields. I suggest either using a calculated field to show the bill amount, or having a field on the master bill record showing the amount actually billed for the detail. Because you probably want to know what was actually billed, it is best to store that information with a calculated field that lets you see easily whether changes happened to the bill information since the invoice was generated. The invoice form would be relatively simple; have one button to generate an individual invoice by going to a master bill record (you could also have this button on the bill record for the billing information form) and a second button to generate invoices for all unbilled master bill records.

The second method would be to have a bill cycle for customers and have the invoices generate on the bill cycle. This setup works well for something like lawn service, where the service comes three times per month and sends a bill out at the end of the month. You could enter a record in for each time the lawn was serviced, and at the end of the customer's bill cycle, an invoice could be created.

Whichever method you choose, whether you come up with a combination of those methods or one of your own, the general idea is to have an invoice created in Excel. This gives you the option of either creating the entire invoice from scratch or using an Excel workbook as a template. That choice is up to you. From the client's perspective, it is probably best to use a template because this allows them to make changes without additional programming.